#include <iostream>
#include <string>

using namespace std;

int main()
{
	char c;
	string str;
	while(cin >> c)
	{
		if(c == 'a')
		{
			cout << "yes" << endl;
			getline(cin,str);
			continue;
		}
		else if(c == '.')
		{
			cout << "no" << endl;
		}
	}
}